Preset releasing sub assembly



May 20, 1952 K. E. WAGGENER 2,597,414

PRESET RELEASING SUB ASSEMBLY Filed Jan. 12, 1948 I Ill/ 1 L u mmvron,

' '41970/ 215 fig I BYZb Patented May 20, 1952 UNITED STATES PATENT GFFICE 6 Claims.

This invention is a drilling, bumper sub and safety joint and has to do with advancements in that type of sub shown in application Ser. No. 729,915, filed February 21, 1947, now Patent 2,572,895 issued October 30, 1951.

Drill pipe generallybecomes stuck while drilling, or'while the string of pipe is being Withdrawn from the hole: Because the diameter of the bit and, collar is usually the largest in the made up string of pipe it is usually the collar assembly that freezes in the hole, either at the bottom or at some higher level as the tool string is being pulled. If a sharp jarring blow of considerable intensity can be given the collar, as soon as possible after it becomes stuck, the string can ordinarily be loosened for further drilling, or for pulling as the case may be.

Numerous releaseable subs and jars have been introduced. Such jars have embodied a form of friction-principle release controls, and they have a most serious jeopardy in that the amount of tripping load put on the release may so greatly vary at the instant of release that the jar imparted to the collar may often be far too low in intensity to loosen the tool from the earth formation holding it. With the knowledge of such imperfection of friction-type releases it is an object of this invention to eificiently meet the problem and the hazards by providing a bumper sub release means which will require a positive and known load before the release can possibly trip off. In other words, an object of the invention is to provide a non-friction-principle release device incorporating a feature which can be preset at the derrick or shop floor to a precise, known degree of resistance which must be overcome when the jar is in the hole or well before the re lease is effected.

Further, an object of the invention is to provide a bumper sub in which means are incorporated to give a hi h degree of lateral stability as between the bottom, internal mandrel and the lower end of the bumper barrel which houses the mandrel stem and is slidable therealong in the releasing and the re-setting functions.

Also, an object of the invention is to provide means enabling the ready, quick and reliable unhitching of the barrel from the mandrel in the event that the latter cannot be pulled from a hole by the barrel and its suspending drill pipe.

The invention resides in certain advancements in this art as set forth in the ensuing disclosure and having, with the above, additional objects and advantages as hereinafter developed, and whose constructions, combinations and subcombinations, and details of means and manner of operation will be made manifest in the following description of the herewith illustrative embodiment; it being understood that modifications, variations and adaptations may be resorted to within the scope, spirit and principles of the inventicn as it is claimed in conclusion hereof.

Figure 1 is an elevational, axial section of the sub with the parts in normal drilling position.

Figure 2 is a somewhat larger scale, detail sectional view showing the barrel in unlocked relation as to the sub mandrel for withdrawal therefrom.

Figure 3 is a cross-section on line 3-3 of Fig. 2.

Figure 4 is a cross-section on line 4-4 of Fig. 1.

Figure 5 is an elevational, axial section, and Fig. 6 is a broken away plan of a laminated type, discal spring unit such as employed in the sub. Figure 7 is a sectional detail, showing springcompression. Fig. 8 is an elevational view of the finger sleeve.

In the embodiment shown a mandrel body 2 has on its lower end. a screw pin 3 for attaching to a subjacent assembly, a tool collar for instance. The body 2 has also an external shoulder forming an anvil 4 to be impinged by the adjacent hammer end H of the barrel 3 of the sub assembly described subsequently.

The barrel has screwed onto its top a coupling 5 for attachment to upper drill pipe or other equipment, not shown, and by which the instant jarring sub is lowered, or raised, or rotated to right or to left, as needed. The barrel is telescoped on the mandrel body 2. A feature of the present invention resides in a practical and simple means whereby the mandrel is normally suspended in and by the barrel with the anvil 4 in a predetermined spaced position below the hammer end H and which means permits of the ready withdrawal of the barrel from the mandrel if and when it is stuck in a hole and cannot be pulled out. And, additionally, this means has the function of laterally stabilizing the assembled sub barrel and its mandrel.

This particular means here includes a lower set of rigid, peripherally spaced, downwardly pitched wedges 6, and a like upper set of rigid wedges 1 on the body mandrel at a suitable height above the anvil; the wedges of said sets being in longitudinal alignment to facilitate extraction of the barrel from the sub, if need be. The lower wedges are adapted to snugly seat on a complementary set of annularly spaced spurs 68 on the inner surface of the barrel, and the upper wedges l likewise seat on a complementary set of higher up spurs is on the barrel inner surface. From this arrangement of hanging spurs and mandrel wedges it will be seen that a rigid suspending connection is had between the barrel and its mandrel. By slightly lowering the barrel it and its spurs 6S and is can be freed from the wedges and the barrel can then berotated left-hand direction (looking down from the barrel top end) to allow the spurs to pass up freely between the spaced wedges if and when the barrel is elevated.

For rotational drive of the mandrel it has, between the upper and lower sets of wedges and spurs, a set of rigid, elongate bars 8 widely spaced around the mandrel, Fig. 3, to permit of necessary side shift of a plurality of rigid keys 9 on the inner surface of the barrel and which reciprocate on the mandrel. In the normal suspended position of the mandrel 2 the keys 9 are locked against untoward rotation on the mandrel by stop lugs I and the barrel can rotate the mandrel in either direction, as desired. When the barrel is lowered to the anvil 4 of the mandrel, keys 9 are engaged by lower lugs II, which are alined with the upper lugs ID and enable right or left rotation of the mandrel. It is necessary to provide for upward escape of the barrel keys 9 when the barrel is to be pulled from the mandrel, as needed. Therefore the lungs I 0 are spaced a distance above the lower lugs I I somewhat greater than the length of the barrel keys 9 and when the barrel is shifted up or down to register the keys with the gap I2, Fig. 2, the barrel can be rotated left hand wise (looking down from top of the sub). As soon as the keys 9 are longitudinally free of the stop lugs I I then the suspending spurs 6S and 1S, and the keys will be in a position to pass up clear of the top set of wedges 'I of the mandrel.

The mandrel 2 is hollow for the free flow of fluids.

In the well drilling industry it is highly desirable that the barrel can be jarred down onto the subjacent drill collar with certainty of a positive minimum force. This has not been possible heretofore for the reason that such automatic tripping means as has been available was too dependent on the frictional slip off of relative tripping elements.

Means are provided in this invention whereby to positively, mechanically lock the barrel and the mandrel against any longitudinal, relative shift until a known and preset degree of pressure has been placed on the mandrel and transmitted to the tool collar, before the trip off of the jar control can occur. When such a necessary down pressure has been set up in the jarring sub then and then only can the controlling trip off means be disengaged and the barrel be allowed to snap down against the anvil of the sub.

The trip off control device here includes an inner sleeve I5 slidably fitted in the bore of the barrel B and having a circle of outwardly yieldable, normally contracting spring fingers I5 downwardly resting on the upper, suitably conical end face I6 of the upper, reduced portion of the mandrel 2. A locking bushing I! is adjustably threaded in the barrel at the position of the upper end of the mandrel and slightly above the saidface I6 thereof so as to normally surround the lower ends of the fingers I5) and positively lock them in place on said face against expansion. The threaded bushing is depressed, or raised, with and by the barrel. This bushing I I also functions to compress a packing I8 between the mandrel and the bore face of the barrel.

Before the contracted spring fingers I5 can.

be thrust outward off of the mandrel end face I6 it is necessary that the locking ring or bushing I! be depressed by and with the barrel far enough to allow such action to occur. Means are therefore provided which will allow the barrel to move down relative to the sleeve I5 resting on the mandrel when a predetermined drill string load, in drilling operations with the sub, is permitted to accumulate on the sleeve I5 while it is standing on the arrested mandrel. Such a control means here includes a stack of spring units, Figs. 5 and 6, each comprising a form of laminate spring. Each such spring includes a pair of flat, resilient rings 20 each having around its bore hole margin a notched, circular land 2|; these lands meeting face to face for downward transmission of pressure, ring to ring.

On the flat top and bottom faces of the two inner rings 20 are positioned respective rings 22 lying flat on the inner rings and having suitably concaved outer faces 22C presenting outer ridge rims 22R. The stack of these spring units is introduced into the complementary bore of the barrel Bridge rim to ridge rim, and land to land, and lodge at the top against the adjacent end face of the top (sub) coupler 5, Fig. 1, in which freely slides the upper end of a pipe 23 forming a supporting core for the stacked spring units. The spring units are stacked on this core 23 before the stack is placed in the barrel B, and the core stays them against axial disalinement.

The stack of springs 20-22 is initially, before installation in the barrel compressed by a nut 24 screwed onto the core pipe 23 to set against a pipe shoulder 233; this all constituting a preset spring assembly to be positioned in the barrel, as just above stated. The degree of compression of the spring stack determines the tool string pressure needed to trip the sub in the barrel. When the spring stack is positioned in the barrel the lower end of the stack engages a tubular, short spacer or shim 25 and as the top coupling 5 is screwed in on top of the spring stack the stack is further slightly compressed according to the length of the jack spacer 25 and the nut 24 becomes slightly spaced, as in Fig. 1, from the bottom of the spring stack, and the pipe 23 hangs by its shoulder 23s on the top end of the pre-compressed spring stack. The spacer 25 (which is slidable in the barrel with the sleeve I5) rests on the upper end of the mandrel supported, finger ring or sleeve I5 with a given load controlled by the pressure 'to which the stack of springs 2022 is compressed between the coupler 5 and the jack spacer 25. As that load is approached by downward movement of the barrel B the locking screwed-in bushing Il moves down with the barrel until finally the bushing clears the tips of the mandrel-arrested engaging fingers I5f and the back bevelled face It of the mandrel body will allow the fingers to snap outward and allow the barrel to move downward toward the anvil 4.

. As the locking bushing I'I moves down past the face I6 the fingers I5 are forced out and lodge on the now depressed bushing face 11), the spring stack being additionally compressed as this unlocking action takes place. As soon as the fingers I5 lodge on the lowered bushing I! the latch ring and the spring device 20-22 act as a unit with the released barrel.

By a pulling operation on the drill string the barrel B is again shifted up along the mandrel 2 and the fingers I5f spring inwardly from the face I If of the bushing I1 and this again locks the contracted fingers on the end face I6 of the mandrel ready for another tripping action; the spring load thus again being transferred to the mandrel by way of the sleeve I5. The barrel is now ready for a repeat jarring action, or continued drilling, or lowering of the tool if it has been struck free by the previous jar impact.

It will be seen that by using one or another of spacers 25 of clifierent length the tripping load by the barrel can be readily pre-determined, since the length of the employed. jack spacer determines the compression of the spring stack against the coupler 5.

The operation is as follows:

When the sub assembly parts are set in the position, Fig. 1, the spring 29-22 is compressed between the barrel coupling 5 and the shim or spacer 25 which latter is standing on the sleeve l5 whose fingers l5 stand in contracted position on the cam face "5 of the mandrel. The fingers are at this position locked against outthrust of the cam by the locking bushing ll (fixed in the barrel). The re-action of the spring 29-22 is pulling the barrel up so that its spurs is jam up on the mandrel wedges 7. If the tool is in the act of being lowered as a unit the mandrel is hanging as Well as springpressed on the spurs ls. Ifjt is desired to strike a down-jar effort on the mandrel, assuming that it is either bottomed or stuck in a well hole, all that is necessary is to let the barrel slowly down as to the mandrel until enough weight of the barrel overcomes the spring 2922. The consequence is that the resistance of the cam it against the sleeve fingers [5 permits a downward shift of the barrel along the mandrel and finger supported sleeve l5 to an amount that will shift the bushing l1 below the contracted finger tips (of fingers [5 At this instant the cam l6 forces the unlocked fingers outward and they will grip and slide down along the upper end portion of the mandrel and the hammer I-I will strike the anvil. The lock nut 29 on the wash pipe 23 comes into use only when the spring pile is being installed pre-compressed in the barrel and until the coupling 5 compresses the spring onto the spacer 25. By using spacers of different axial length selection of one of the variety will provide for various degrees of pre-compression of the control spring.

What is claimed is:

1. A pre-set, releasing, tool string sub including a tubular mandrel whose upper end is provided with an outwardly and downwardly bevelled cam face, a barrel telescopic on said mandrel and having fixed inner seat-forming spurs and complementary wedges therefor on the mandrel to suspend the mandrel from the barrel, key and spline means connecting the barrel and the mandrel for corotational drive by the barrel, a hammer part on the barrel and an opposed anvil on the mandrel, and means for trippably latching the barrel on the mandrel in a position to space the hammer part above the said anvil for jar stroke of the barrel; said means including a sleeve slidably fitting the inner face of the barrel and having a set of normally contracting, inwardly inclined resilient latching fingers to rest on said cam face and being spaced from and expansible toward the bore face of the barrel, a locking bushing fixed in the barrel and normally retaining said fingers in contracted, strut-forming position on said cam face, and a spring of predetermined resistance reacting downward on said sleeve to force the fingers onto said mandrel cam face and bring said spurs and wedges together, and which spring is confined at its top by a fixed part of the barrel; said fingers being released from said bushing when downward pressure by downward movement of the barrel overcomes the resistance of the spring and shifts the locking bushing, as it moves down with the barrel, from the said fingers and thereby rereleases the barrel to effect a hammer stroke thereof on the mandrel.

2. The sub of claim 1; and a landing compression determining spacer interposed between the sleeve and the lower end of the said spring.

3. The sub of claim 1; and including a means for pre-compressing the spring before it is installed in the barrel comprising a hollow core freely slidable in the contiguous portion of the barrel and on which the spring is telescoped and seated at one end, and a nut threaded on the said core and engaging and to pre-compress the spring on the core before it is installed in the barrel.

4.-. A pre-settable, trip controlling assembly adapted for bodily installation in or removal from deep well tool string and including a spring structure of generally cylindrical form, a tubular core freely telescopically fitting in a portion of the string and having an external shoulder and a threaded portion, and a nut on said portion for compressing said spring structure along the core and against said shoulder to constitute a pre-compressed, insertible unit independent of the string structure; the spring structure having ends adapted to seat on contiguous abutments presented in a part of said tool string, when parts of the string are assembled, for further spring compression.

5. A well tool string including a barrel presenting a sliding interior abutment sleeve, an internal mandrel on which the sleeve is ar-' rested, a spring structure telescoped in the barrel and seating on said abutment sleeve, a core on which the said structure is fitted and having a stop therefor at one end, a nut threaded on said core to pre-compress the spring structure against said stop before the core and spring are installed in the barrel as an assembled unit, and a fitting screwed in the barrel and engaging and additionally compressing said structure onto said interior abutment sleeve; said nut telescoping in said sleeve.

6. The combination of claim 5, said mandrel having an annular conical cam on its top edge, a bushing fixed in the barrel and normally surrounding said cam, and a set of resilient latches fixed to the lower end of said sleeve and automatically contracting to latching position on said cam; said cam being in operative engagement with complementary faces of and operative to expand the latches and release the barrel as it and the bushing move down and overcome the pre-compressed spring structure and clear the ends of the latches.

KENNETH E. WAGGENER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,954,513 Beck Apr. 10, 1934 2,008,743 Black July 23, 1935 2,008,765 McCullough July 23, 1935 2,056,496 White Oct. 6, 1936 2,126,241 Black Aug. 9, 1938 2,166,299 Kennedy et al. July 18, 1939 2,309,866 Reed Feb. 2, 1943 

